ITEM 502  STRUCTUREs for maintaining traffic

502.01  Description

502.02  Design and Construction

502.03  Maintenance

502.04  Removal

502.05  Basis of Payment


502.01  Description.  This work consists of preparing plans, providing, maintaining, and subsequently removing temporary structures.

502.02  Design and Construction.  As a minimum, design the temporary structure for a 5-year flood or with 75 percent of the effective waterway opening of the proposed structure.  The Contractor is responsible for any damages caused by upstream flooding due to insufficient temporary structure size or the accumulation of debris or sediment in the channel.  Provide a clear roadway width of at least 23 feet (7.0 m) measured from face to face of guardrails.  If the existing structure or approaches or both have sidewalks provide at least one sidewalk at least 5 feet (1.2 m) wide with adequate connections to existing walks and in compliance with accessibility standards.

Design the temporary structure according to the AASHTO LRFD Bridge Design Specifications except that the design live loading, HL-93 may be reduced by 25 percent.

Submit  working drawings in accordance with 501.05.

Drive piling to sufficient penetration to carry the superimposed loads according to Item 507, but not less than 24 tons (24 metric tons) per pile.  Perform dynamic load testing to determine required blow count if piles are not driven to rock.

If the plans state that the existing superstructure may be used instead of new construction, do not alter it to meet either the above width or strength requirements.  Instead, move or dismantle and re-erect with sufficient care to avoid any reduction of capacity.  If the superstructure has been restricted by posting to loads less than permitted by statute, move the posting signs to the temporary road, unless the superstructure is strengthened to a legal load capacity.  If planning to use the existing superstructure on the temporary road, notify the Engineer at least 3 days before the superstructure is moved to allow the Department to establish a detour.  Complete the bridge within 48 hours after traffic has been routed over the detour.

502.03  Maintenance.  Maintain all portions of the temporary structure in good condition with respect to both safety and smoothness for travel as long as it is needed for maintenance of traffic. Satisfactorily maintain the channel and waterway opening.

502.04  Removal.  If the temporary structure is no longer needed, take ownership and remove it from the site according to Item 202.

502.05  Basis of Payment.  Payment is full compensation for erection, maintenance, performing dynamic load testing, and subsequent removal of temporary structures.

The Department will pay for accepted quantities at the contract price as follows:

Item           Unit                                Description

502             Lump Sum              Structure for Maintaining Traffic